Fuel burner



March 12, 1935. R. M. HARDGROVE y 1,994,446

l FUEL BURNER Original Filed Jan. 14, 1928 3 Sheets-Sheet 1 March 12,1935. R. M. HARDGRovE 1,994,446

FUEL BURNER Original Filed Jan. 14. 1928 3 Sheets-Sheet 2 mw y1/V32ATTORNEY March 12, 1935. R. M. HARDGROVE 1,994,446

FUEL BURNER Original Filed Jan. 14, 1928 3 Sheets-Sheet 3 v INV TOR n lAwrs FIGS.

FIGB.

Patented Mar. l2, 1935 FUEL BURNER Ralph M. Hardgrove, Westfield, N. J.,assigner to Fuller Lehigh Company, corporation of 'Delaware Fullerton,Pa., a

original application January 14, 192s, serial No.

246,710. 7,1929, serial No. 397, 2.6, 1934 This invention relates to afuel burner that has an inlet for primary air and fuelvand a separateinlet or inlets for secondary air. This is a di. vision ofmy applicationSerial No. 246,710,1iled 5 January 14, 1928. The invention understoodfrom the description in connection with the accompanying drawings, inwhich Fig. 1 is a front view. with parts omittedshowing an illustrativeembodimentA ofthe invention installed'in a furnacewall; Fig. 2- isasection along, the line 2--2-of Fig. 1;'Fig. 3 is a section along'theline 3--3 of Fig. 4 including adjacent tubes; Fig. 4 is a front'viewpartly brolrenawayl showing a modification; Fig. f-is a.` sectionvsimilar to Fig.

5 l 2 throughanother modification: Fig. 6 isa frontv view of Fig. 5; andFig. 7 is a section 'on an enlarged scale vshowing a detail.

The invention will be described in connection with a boiler furnace, inthe walls of which' water o tubes are installed for keepingrthe wallscool, but the invention is not restricted to this particular sort offurnace. In the drawings, reference chary acter 5 indicates the watertubes to which blocks. 6 are connected to form the wall of a furnace,these blocks being preferably Imadev up of refractory material on theside next tothe furnace and metal on the other side which contacts withthe water tubes. Two of the tubes are bent outwardly, as indicated at'7, to facilitate installation of the fuel o burner. A conduit 8 forprimary -air and fuel,

such as pulverized coal, gas, etc., ,having an elongated exit opening 9is attached to the tubes 7. A casing 10 into which secondary air for combustion purposes may be introduced in any con--v 5 venient way,surrounds the conduit 8 and is con-K nected/to theI furnace wall soas'fto be air tight. Blocks l1 on opposite sides of the two tubes '7/are spaced apart in staggered relation, s o as to e leave staggeredopenings l2 on opposite sides of 0 the pair of -tubes 7 through whichopenings secondary air isadmitted from the casing 10. The secondary airentering through the openings l2 impinges against the sides of thestream of fuell entering through the exit opening 9 andcauses `5thorough commingling of the fuel and air.

A fuel burner of the type above described has been known heretofore.With'such burners it has been found vthat when they are operating atdecreased loads with smaller amounts of seci0 ondary air enteringthrough the ports or openings 12, the velocity/of the air is sometimesdecreased so much that satisfactory commingling of the fuel and air nearthe mouth of the burner'` is not obtained. By the present invention,-the i5. velocity of the secondary air is maintained suf.-

Divlded and this application October e ings, .the pressure of the largevolumev of second- 78 6. Renewed' January claims. (ci. 11o-2s).cientlyxhigh even when decreased amounts of secondary air are beingsupplied. In carrying out the invention, means are provided by which'thesine of the ports or openings 'l2 for the secondary air may be decreasedwhen 5 .the rate of supply of secondary air is decreased,v lthus keepingthe velocity of the air sufficiently greatl to cause the air tocommingle withrthe fuelv asv the air impinges against the 'fuel stream.In the illustrativev embodiment of the invention, *1 and 2,.two sets ofvertically spaced dempers 15v at opposite sides of thel fuel exitopen-,ings are mounted on vertical pivot rods 16 and are movable acrosscorresponding air. ports or openings 12 in accordance with the amount of15 air' that is to' be'delivered. Each damper '15 has an arcuate innerside 1 1 that is moved on turning of the corresponding pivot rod 16 tovary the effective area of a corresponding port 12.' Each 'l damper alsohas a vertical concavely curved side 13V which extends beyond thearcuate shaped side 17, as shown at 19, into the'corres'pondin'g portl2.`

The pair of pivot rods 16 are spaced apart within thecasing 10 and haveoppositely extending arms 20 and 21 respectively connected to the lowerportions thereof. A connecting rod 22 provided `with a turnbuckle 23forV adjusting the length thereof connects the inner free end of the arm21 to a pivot .pin 24, asfshown in Fig. 7, having a threaded extension25, that is adjustable in a slot 26formed in the arm 20.

Aerod 30 is pivoted tothe outer end of the arm 20 and passes throughtheside Wall of the casing 10 and through an external stop member 31adapted to be xed thereon by a set screw 32. A washer 33 bears againstAthe stop 31 and a washer 34 bears against a nut 35 on the outer threadedend of the rod 30. A compression spring 36 is interposed between thewashers 33 and 34 which tends to move the rod 30 when loose toward theright, as shown in Fig. 2, to thereby move the dampers towards theirclosed positions. The set screw .32 is loosened Whenever the airpressure in the dampers 15 into their open positions by its passagealong the concave surfaces 18, and since the volume of the air is large,the velocity of the same passing through the ports or openings 12 willbe suflicient to cause thorough commingling of the air and fuel.Thesunbalanced pressure on the sides of the projecting damper portions19 opposite the air streams aids ln opening the dampers and compressingthe spring 36 in accordance with the amount of secondary air that isbeing supplied. When the amount of secondary air is decreased forsmaller ratings, the expansion of the spring 36 causes the dampers 15 tobe moved toward their closed positions, thus decreasing the size of theports 12 with decreased amounts of secondary air, so that the velocityof the smaller amount of air entering through the smaller air openingswill be sufficient to 'cause the secondary air and fuel to be properlycommingled.

The provision of.the slot 26 in the arm 20, by means of which the outerend of the rod 22 that is connected to the arm 21 can be adjusted todifferent positions, makes it possible to vary the extent to which thetwo sets of dampers can be closed with respect to each .other fromuniformityof extent of opening and closure of the two to an extent towhich the dampers on the left hand side would be opened and closed onlya small fraction of the extent of the dampers onthe right hand side.

It will be clear that the spring 36 will cause the'damper's to beYclosed automatically in ac` cordance with thereduction in the secondaryair supply. The velocity of the air will thus be kept approximatelyconstant regardless of the quantity of air passing through each airinlet. However, by means of the'setscrew 32 and adjustment ofthe bracket25 in the slot 26, the dampers can be set in any desired fixed positionfor conditions of operation where the rate is constant or nearly so, ata predetermined load.

In the illustrations shown in Figs. 3 and 4 the fuel and primary airstream entering through the conduit 8 is caused to divide into aplurality of stagged streams that diverge on opposite sides so that thesecondary air entering through the secondary air openings will strikethese streams substantially at right angles thus causing bettercommingling of the fuel and air. In these illustrations the blocks l1'are shaped to leave staggered openings 12' and 12" on opposite sides ofthe primary air and fuel'inlet.

'Ihe blocks 11' have extensions 40 and 41, Figs.

3 and 4, staggered with respect to each other and corresponding to theopenings 12' and 12", respectively, located along the sides of theelongated exit opening` of the conduit 8. 'I'he extensions 40 and 41have sloping. faces 42 so that the primary air and fuel passing throughthe exit opening will be thrown in staggered streams in front ofcorresponding openings 12' and 12".

By this arrangement the entering fuel stream is divided into a verticalseries of alternately oppositely diverging streams, each of which is fimpinged upon by a corresponding air stream at substantially rightangles thereto.

In the modification shown in Figs. 5 and 6 staggered blocks 45 areattached to the tubes 7 on opposite sides of the elongated fuel nozzle`exit opening 9 for the same purpose as the extensions 40 and 41 in Figs.3 and 4.

1. In a furnace, a fuel burner having an inlet for primary air and fuelshaped to provide a at ary air that is required is sufficient to forcethe stream of saidfair and fuel, staggered secondary air inlets onopposite sides of laid primary air and fuel inlet, -and means to causesaid primary air and fuel `to enter the furnace substantiallye at rightangles to the direction of entry of the secondary air.

1 2. In a furnace, a fuel burner' having an inlet for primary air andfuel shaped to provide a flat stream of said air and fuel, staggeredsecondary( air inlets on opposite sides of said primary air and fuelinlet, and means to cause the primary air and fuel to divide into aplurality of streams passing into thefurnace on said secondary airinlets.`

3. In a\furnace,a fuel burner having an inlet for primary air and fuelshaped to provide a dat stream of said air and fuel, staggered sec-fondary air inlets on opposite sides of said primary air and fuel inlet,and extenslonson opposite sides of said primary air and fuel inletopposite said secondary air inlets directing the primary air and fueltowards correspon secondary air inlets.

4. In a furnace, a fuel burner having an inlet for primary air and fuelshaped to provide a flat stream of said air and fuel, staggered.secondary air inlets on opposite sides of said primary air and fuelinlet with directions of entry of the air therethrough at an angle toeach other and means to cause said primary air and fuel to enter thefurnace substantially at right angles to the direction of entry of `thesecondary air.

5. In a furnace, a fuel burner having an inlet for primary air and fuelshaped to provide a` nat stream of said air and 4fuel, staggeredsecondary air inlets on opposite sides of said. primary air and fuelinlet, and means with projections having sloping faces to cause saidprimary air and fuel to enter the furnacesubstantially at right anglesto the direction of entry of the secondary air.

6. In a furnace; a fuel burner having an inle for primary air and fuelshaped to provide l.I flat stream of said air and fuel, staggered inletsfor secondary air on opposite sides of said primary air and fuel inlet,means to cause said primary air and fuel to enter thefurnacesubstantially at right angles to the direction of entry of thesecondary air, and means to cause the secondaryair to enter the furnacein streams on opposite sides of said burner directed towards each other.

'1. In a furnace, a fuel burner having an inlet for primary air and fuelshaped to provide a flat stream of said air and fuel, staggered inletsfor secondary air on opposite sides of said primary air and fuel inlet,means to cause said primary air and fuel to enter the furnacesubstantially at right angles to the direction of entry of the secondaryair, and means to cause the secondary air to enter the furnace instreams on opposite sides of said burner at acute angles to the furnacewall;

8. In a furnace, a fuel burner having an inlet for primary air and fuel,staggered secondary air inlets on opposite sides of said primary air andfuel inlet, extensions -on oppomte sides of said primary air and fuelinlet opposite' said respective secondary air inlets, and water cooled,tubes to which said extensions are'connected.

9. Ina furnace, a fuel burner, means to cause primary air and fuel toenter the furnace in a plurality of streams, and means to directsecondary air in streams against said streams of' primary air and fuel,said last named means comthe, furnacel side of.v i

'nsl

prising spaced blocks staggered of said burner.

10. In a furnace wall comprising spaced tubes, a fuel burner having afuel discharge opening between apair of adjacent wall tubes, an airinlet port adjacent said discharge opening, and means on opposite sidesforming a continuation of at least a portion of the discharge endy ofsaid fuel burner and in direct thermal contact with one of said pair ofadjacent wall tubes for deecting discharged fuel across' impinging onand commingling with a corresponding fuel stream.

12.,Ir i combination, a furnace wall having a series of spaced coolingfluid tubes, a fuel burner having nozzle means arrangedto discharge fuelbetween adjacent tubes in a pl ality of streams alternately oppositelydirecte staggered air inlet ports at opposite sides of said fuel burnernozzle means and opening to the furnace between adjacent tubes, andmeans for supplying air for combustion to the furnace through said airinlet ports in high velocity jets impinging on and commingling withcorresponding oppositely directed fuel streams.

13.1In combination, a furnace wall having a series of spaced verticallyextending cooling fluid tubes at its furnace side, a. fuel burner portin said Wall, a fuel burner having nozzle means for discharging fuelthrough said port and between adjacent tubes in a plurality of streamselongated parallel to said tubes and alternately directed in divergingdirections, air inlet ports at opposite ing to the furnace betweenadjacent tubes, and means for supplying air for combustion to the,furnace through said air inlet ports in separate high velocity jetseach directed towards and impinging on an oppositely directed fuelstream.

14. In combination, a furnace wall having a series of spaced verticallyextending cooling huid tubes at its furnace side, a fuel burner port insaid wall, afuel burner having nozzle means'for discharging fuel throughsaid port and between adjacent tubes in a stream elongated transverselyof the direction offuel discharge, a plurality of staggered air inletportsat opposite sides of said fuel burner inozzle means and betweenadjacent tubes, means for supplying air for combustion to the furnacethrough said air inlet ports in separate high velocity jets directedtowards said fuel stream, and deflectors at the outlet end of said`nozzle means for de'ecting adjacent portions of said fuel streamrespectively across air inlet ports at opposite sides of said nozzlemeans.

15. In combination, al furnace wall having a fuel burner opening formedtherein, a fuel burner comprising a nozzle adapted to discharge a streamof pulverized fuel and primary air through said wall opening, saidnozzley having walls arranged sides of said fuel burner nozzle means andopenat its discharge end to form an oblong outlet with the boundingedges of opposite walls thereof sub-f! stantially parallel, a pluralityof deiiector members positioned along at least one of saidopposing edgesat points spaced along the length thereof and arranged to extend intothe path of the disf charge of said nozzle to form a discharge streamwith alternate diverging portions, and secondary air discharge means insaid furnace wall at opposite sides of said nozzle constructed andarranged to direct streams of secondary air towards and impinging oncorresponding portions of said discharge stream.

RALPH M; HARDGROVE.

